Replication

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Across
  1. 4. added to the newly exposed bases on the lagging strand and DNA synthesis occurs in fragments
  2. 5. enzymes that work by temporarily breaking the DNA backbone, allowing the twisted strands to relax and unwind/to relieve the stress in a supercoiled strands
  3. 7. fragments that synthesised in the 5′ to 3′ direction as before.
  4. 10. DNA polymerase is only able to extend the primer by adding free nucleotides to the 3’ end. One of the template strands is read in a 3’ to 5’ direction, therefore the new strand will be formed in a 5’ to 3’ direction. DNA primase only needs to synthesise an RNA primer once, at the beginning, to initiate DNA polymerase. This is because DNA polymerase is able to extend the new DNA strand by reading the template 3′ to 5′, synthesising in a 5′ to 3′ direction as noted above.
  5. 12. proteins bind to the newly separated individual DNA strands to keep the strands separated / stabilize DNA
  6. 13. creates two new double helices with one old and one new strand each
  7. 14. attached to the two unzipped strands of DNA , it is able to start synthesising new strands of DNA to match the templates.
  8. 15. DNA _____ seals fragments together to create continuous complete strand.
Down
  1. 1. enzyme that synthesises a small RNA primer, which acts as a ‘kick-starter’ for DNA polymerase. This enzyme is ultimately responsible for the creation and expansion of new strands of DNA.
  2. 2. enzyme unwinds the double helix and exposes each of the two strands so that they can be used as a template for replication. It does this by hydrolysing the ATP used to form the bonds between the nucleobases, thereby breaking the bond holding the two strands together.
  3. 3. original double-stranded DNA molecule remained entirely intact after replication
  4. 6. removes the RNA primer at the beginning of each Okazaki fragment
  5. 8. template strand read in a 5’ to 3’ direction.
  6. 9. The process of expanding the new DNA strands continues until there is either no more DNA template strand left to replicate at the end of the chromosome or two replication forks meet and subsequently terminate.
  7. 11. parental DNA strands fragment and intersperse with newly synthesized segments throughout the daughter molecules